System and method for processing speech

ABSTRACT

Systems and methods for processing speech are provided. A system may include an acoustic model to transform speech input into one or more word strings. The system may also include a semantic model to convert each of the one or more word strings into a detected object and a detected action. The system may also include a synonym table to determine a preferred object based on the detected object and to determine a preferred action based on the detected action.

CLAIM OF PRIORITY

This application is a Continuation Patent Application of, and claims priority from, U.S. patent application Ser. No. 11/005,494, filed on Dec. 6, 2004, and entitled “SYSTEM AND METHOD FOR SPEECH RECOGNITION-ENABLED AUTOMATIC CALL ROUTING,” which is hereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to speech recognition and, more particularly, to speech recognition-enabled automatic call routing service systems and methods.

BACKGROUND

Speech recognition systems are specialized computers that are configured to process and recognize human speech and may also take action or carry out further processes. Developments in speech recognition technologies support “natural language” type interactions between automated systems and users. A natural language interaction allows a person to speak naturally. Voice recognition systems can react responsively to a spoken request. An application of natural language processing is speech recognition with automatic call routing (ACR). A goal of an ACR application is to determine why a customer is calling a service center and to route the customer to an appropriate agent or destination for servicing a customer request. Speech recognition technology generally allows an ACR application to recognize natural language statements so that the caller does not have to rely on a menu system. Natural language systems allow the customer to state the purpose of their call “in their own words.”

In order for an ACR application to properly route calls, the ACR system attempts to interpret the intent of the customer and selects a routing destination. When a speech recognition system partially understands or misunderstands the caller's intent, significant problems can result. Further, even in touch-tone ACR systems, the caller can depress the wrong button and have a call routed to a wrong location. When a caller is routed to an undesired system and realizes that there is a mistake, the caller often hangs up and retries the call. Another common problem occurs when a caller gets “caught” or “trapped” in a menu that does not provide an acceptable selection to exit the menu. Trapping a caller or routing the caller to an undesired location leads to abandoned calls. Most call routing systems handle a huge volume of calls and, even if a small percentage of calls are abandoned, the costs associated with abandoned calls are significant.

Current speech recognition systems, such as those sold by Speechworks™, operate utilizing a dynamic semantic model. The semantic model recognizes human speech and creates multiple word strings based on phonemes that the semantic model can recognize. The semantic model assigns probabilities to each of the word strings using rules and other criteria. However, the semantic model has extensive tables and business rules, many that are “learned” by the speech recognition system. The learning portion of the system is difficult to set up and modify. Further, changing the word string tables in the semantic model can be an inefficient process. For example, when a call center moves or is assigned a different area code, the semantic system is retrained using an iterative process.

Further, speech recognition systems are less than perfect for many other reasons. Accordingly, there is a need for an improved automated method and system of routing calls.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified configuration of a telecommunication system;

FIG. 2 is a general diagram that illustrates a method of routing calls;

FIG. 3 is a flow diagram that illustrates a method of processing and routing calls;

FIG. 4 is a table that depicts speech input and mapped synonym terms; and

FIG. 5 is a table illustrating action-object pairs and call destinations relating to the action object pairs.

DETAILED DESCRIPTION OF THE DRAWINGS

A system and method are disclosed for processing a call by receiving caller input in a speech format and utilizing phonemes to convert the speech input into word strings. The word strings are then converted into at least one object and at least one action. A synonym table is utilized to determine actions and objects. Objects generally represent nouns and adjective-noun combinations while actions generally represent verbs and adverb-verb combinations. The synonym table stores natural language phrases and their relationship with actions and objects. The actions and objects are utilized to determine a routing destination utilizing a routing table. The call is then routed based on the routing table. During the process, the word string, the actions, the objects and an action-object pair can be assigned a probability value. The probability value represents a probability that the word string, the action, or the object accurately represent the purpose or intent of the caller.

Referring now to FIG. 1, an illustrated communications system 100 that includes a call routing support system is shown. The communications system 100 includes a speech enabled call routing system (SECRS) 118, such as an interactive voice response system having a speech recognition module. The system 100 includes a plurality of potential call destinations. Illustrative call destinations shown include service departments, such as billing department 120, balance information 122, technical support 124, employee directory 126, and new customer service departments 128. The communication network 116 receives calls from a variety of callers, such as the illustrated callers 110, 112, and 114. In a particular embodiment, the communication network 116 may be a public telephone network or may be provided by a voice over Internet protocol (VOIP) type network. The SECRS 118 may include components, such as a processor 142, a synonym table 144, and an action-object routing module 140. The SECRS 118 is coupled to and may route calls to any of the destinations, as shown. In addition, the SECRS 118 may route calls to an agent, such as the illustrated live operator 130. An illustrative embodiment of the SECRS 118 may be a call center having a plurality of agent terminals attached (not shown). Thus, while only a single operator 130 is shown, it should be understood that a plurality of different agent terminals or types of terminals may be coupled to the SECRS 118, such that a variety of agents may service incoming calls. In addition, the SECRS 118 may be an automated call routing system. In a particular embodiment, the action-object routing module 140 includes an action-object lookup table for matching action-object pairs to desired call routing destinations.

Referring to FIG. 2, an illustrative embodiment of an action-object routing module 140 is shown. In this particular embodiment, the action-object routing module 140 includes an acoustic processing model 210, semantic processing model 220, and action-object routing table 230. The acoustic model 210 receives speech input 202 and provides text as its output 204. Semantic model 220 receives text 204 from the acoustic model 210 and produces an action-object pair 206 that is provided to the action-object routing table 230. The routing table 230 receives action-object pairs 206 from semantic model 220 and produces a desired call routing destination 208. Based on the call routing destination 208, a call received at a call routing network 118 may be routed to a final destination, such as the billing department 120 or the technical support service destination 124 depicted in FIG. 1. In a particular embodiment, the action-object routing table 230 may be a look up table or a spreadsheet, such as Microsoft Excel™.

Referring to FIG. 3, an illustrative embodiment of a method of processing a call using an automated call routing system is illustrated. The method starts at 300 and proceeds to step 302 where a speech input signal, such as a received utterance, is received or detected. Using phonemes, the received speech input is converted into a plurality of word strings or text in accordance with an acoustic model, as shown at steps 304 and 306. In a particular embodiment, probability values are assigned to word strings based on established rules and the coherency of the word string. Next, at step 308, the word strings are parsed into objects and actions. Objects generally represent nouns and adjective-noun combinations while actions generally represent verbs and adverb-verb combinations. The actions and objects are assigned confidence values or probability values based on how likely they are to reflect the intent of the caller. In a particular embodiment a probability value or confidence level for the detected action and the detected object is determined utilizing the priority value of the word string used to create the selected action and the selected object.

Many possible actions and objects may be detected or created from the word strings. The method attempts to determine and select a most probable action and object from a list of preferred objects and actions. To aid in this resolution a synonym table, such as the synonym table of FIG. 4 can be utilized to convert detected actions and objects into preferred actions and objects. Thus, detected objects and actions are converted to preferred actions and objects and assigned a confidence level. The process of utilizing the synonym table can alter the confidence level. The synonym table stores natural language phrases and their relationship with a set of actions and objects. Natural language spoken by the caller can be compared to the natural language phrases in the table. Using the synonym table, the system and method maps portions of the natural phrases to detected objects and maps portions of the natural spoken phrase to detected actions. Thus, the word strings are converted into objects and actions, at steps 310 and 312 respectively and the selected action and object are set to the action and object that will be utilized to route the call. The action and object with the highest confidence value are selected based on many criteria such as confidence value, business rules etc in steps 310 and 312.

At step 310 and 312, multiple actions and objects can be detected and provided with a probability value according to the likelihood that a particular action or object identifies a customer's intent and thus will lead to a successful routing of the call and a dominant action and dominant object are determined. Next, at step 314, dominant objects and actions are paired together. At step 316, a paired action-object is compared to an action-object routing table, such as the action object routing table of FIG. 5. The action-object routing table in FIG. 5 is generally a predetermined list. When objects and actions find a match, then the destination of the call can be selected at step 318, and the call is routed, at step 320. The process ends at step 322.

Referring back to FIG. 4, as an example, it is beneficial to convert word strings such as “I want to have” to actions such as “get.” This substantially reduces the size of the routing table. When a call destination has a phone number change, a single entry in the routing table may accommodate the change. Prior systems may require locating numerous entries in a voluminous database, or retraining a sophisticated system. In accordance with the present system, dozens of differently expressed or “differently spoken” inputs that have the same caller intent can be converted to a single detected action-object pair. Further, improper and informal sentences as well as slang can be connected to an action-object pair that may not bear phonetic resemblance to the words uttered by the caller. With a directly mapped lookup table such as the table in FIG. 4, speech training and learning behaviors found in conventional call routing systems are not required. The lookup table may be updated easily, leading to a low cost of system maintenance.

In addition, the method may include using a set of rules to convert a word string into an object or action. In a particular example, geographic designation information, such as an area code, may be used to distinguish between two potential selections or to modify the probability value. In the event that the lookup table of the action-object pair does not provide a suitable response, such as where no entry is found in the routing table, the call may be routed to a human operator or agent terminal in response to a failed access to the action-object lookup table.

Traditional automatic call routing systems are able to assign a correct destination 50-80% of the time. Particular embodiments of the disclosed system and method using action-object tables can assign a correct destination 85-95% of the time. Due to higher effective call placement rates, the number of abandoned calls (i.e., caller hang-ups prior to completing their task) is significantly reduced, thereby reducing operating costs and enhancing customer satisfaction. In addition, the automated call-routing system offers a speech recognition interface that is preferred by many customers to touch tone systems.

The disclosed system and method offers significant improvements through decreased reliance on the conventional iterative semantic model training process. With the disclosed system, a semantic model assigns an action-object pair leading to increased call routing accuracy and reduced costs. In particular implementations, the correct call destination routing rate may reach the theoretical limit of 100%, depending upon particular circumstances. In some cases, certain action-object systems have been implemented that achieve a 100% coverage rate, hit rate, and call destination accuracy rate.

The disclosed system and method is directed generally to integration of action-object technology with speech enabled automated call routing technology. The integration of these two technologies produces a beneficial combination as illustrated. The illustrated system has been described in connection with a call center environment, but it should be understood that the disclosed system and method is applicable to other user interface modalities, such as web-based interfaces, touchtone interfaces, and other speech recognition type systems. The disclosed system and method provides for enhanced customer satisfaction because the customer's intent can be recognized by an action-object pair and a high percentage of calls reach the intended destination.

The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description. 

1. A system to process speech, the system comprising: an acoustic model to transform speech input into one or more word strings; a semantic model to convert each of the one or more word strings into a detected object and a detected action; and a synonym table storing data that can be processed to determine a preferred object based on the detected object and to determine a preferred action based on the detected action.
 2. The system of claim 1, further comprising a processor to perform an act based on the preferred action and the preferred object.
 3. The system of claim 2, wherein the performing the act comprises routing a caller to a desired destination.
 4. The system of claim 1, further comprising a processor to determine a dominant action based at least partially on the preferred action, and to determine a dominant object based at least partially on the preferred object.
 5. The system of claim 1, wherein the preferred object and preferred action are determined based at least partially on geographic designation information related to the speech input.
 6. The system of claim 1, wherein the acoustic model transforms the speech input into the one or more word strings based on detected phonemes.
 7. The system of claim 1, wherein the acoustic model assigns probability values to the one or more word strings based on an evaluation of coherency of the one or more word strings.
 8. The system of claim 1, wherein the semantic model parses the one or more word strings to identify nouns to determine the detected object and wherein the semantic model parses the one or more word strings to identify verbs to determine the detected action.
 9. The system of claim 1, wherein the semantic model assigns a first probability value to the detected object and a second probability value to the detected action, wherein the first probability value and the second probability value indicate a likelihood that the detected object and the detected action reflect an intent of a speaker of the speech input.
 10. A method of processing speech, the method comprising: receiving an object detected based on speech input; receiving an action detected based on speech input; determining a preferred object based on the detected object; determining a preferred action based on the detected action; and performing an act based on the preferred object and the preferred action.
 11. The method of claim 10, wherein receiving the object and receiving the action comprises receiving speech input and converting the speech input into text.
 12. The method of claim 11, wherein receiving the object and receiving the action further comprises identifying at least one noun in the text to detect the object, and identifying at least one verb in the text to detect the action.
 13. The method of claim 10, wherein determining the preferred object comprises selecting a most probable object from a plurality of objects, and wherein determining a preferred action comprises selecting a most probable action from a plurality of actions.
 14. The method of claim 10, wherein performing the act comprises routing a call to a destination selected based on the preferred object and the preferred action.
 15. The method of claim 10, wherein the detected object is not phonetically related to the speech input.
 16. The method of claim 10, wherein the detected object comprises a natural language phrase and the preferred object comprises a term related to the natural language phrase.
 17. The method of claim 10, wherein the detected action comprises a natural language phrase and the preferred action comprises a term related to the natural language phrase.
 18. A system to process speech, the system comprising: a synonym table including a plurality of preferred objects associated with a plurality of detected objects and a plurality of preferred actions associated with a plurality of detected actions; and a processor to receive a detected object based on speech input, to select a preferred object from on the synonym table based on the detected object, to receive a detected action based on the speech input, and to determine a preferred action from the synonym table based on the detected action.
 19. The system of claim 18, wherein at least one of the plurality of detected objects of the synonym table includes a natural language phrase including at least one noun.
 20. The system of claim 18, wherein at least one of the plurality of detected actions of the synonym table includes a natural language phrase including at least one verb.
 21. The system of claim 18, wherein at least one of the plurality of detected objects of the synonym table includes a natural language phrase including at least one adjective and at least one noun.
 22. The system of claim 18, wherein at least one of the plurality of detected actions of the synonym table includes a natural language phrase including at least one adverb and at least one verb.
 23. The system of claim 18, wherein the processor determines a first confidence level associated with the preferred object based on the detected object, and wherein the processor determines a second confidence level associated with the preferred action based on the detected action.
 24. The system of claim 18, wherein the processor determines a plurality of preferred objects based on the detected object, and selects a dominant object from the plurality of preferred objects.
 25. The system of claim 18, wherein the processor determines a plurality of preferred actions based on the detected action, and selects a dominant action from the plurality of preferred actions.
 26. The system of claim 18, further comprising an object-action routing module to route a call associated with the speech input, wherein the object-action routing module includes a plurality of call destinations related to object-action pairs.
 27. The system of claim 26, wherein more than 80% of calls processed using the object-action routing module are successfully routed to a desired destination. 